Abradable coatings on flowpath surfaces above the moving metal blade tips in a turbine engine can reduce over tip leakage and improve efficiencies. For example, a rotating part can erode a portion of a fixed abradable coating applied on an adjacent stationary part to form a seal having a very close tolerance. In one example application, an abradable seal can be used to minimize the clearance between blade tips and an inner wall of an opposed shroud, which can reduce leakage or guide leakage flow of a working fluid, such as steam or air, across the blade tips, and enhance turbine efficiency.